1. Field of the Invention
The present invention relates generally to a manifold or header tube for heat exchangers. More specifically, the invention relates to manifolds having a D-shaped profile, and incorporating baffles, end caps, and brackets adapted to the D-shaped profile.
2. Related Art
In known types of tubular headers or manifolds for heat exchangers, at least one baffle is inserted into the manifold to divide the tube into compartments, and the tubular manifold wall is deformed inwardly on each side of the baffles after their introduction in order to secure them in place prior to brazing. Such manifolds and their method of manufacture are disclosed in U.S. Pat. No. 5,233,756 to le Gauyer. Manifolds made in accordance with the method of le Gauyer have substantially circular cross-sections, even after deformation to secure the baffles, and after formation of the tube slots which receive the head exchanger tubes. The deformation of the tubular wall to secure the baffles requires an extra manufacturing step. Further, the dome shaped webs of material between the tube slots have poor strength in their transition to the cylindrical surface of the manifold.
The manifold disclosed in the le Gauyer patent has a generally circular cross-section along its entire length. Although a circular cross-section is preferable from the perspective of overall strength, a generally D-shaped cross-section may be preferable for other reasons. For example, it is easier to form a joint between the manifold and the heat exchanger tubes on a generally planar surface, as found in a manifold of generally D-shaped cross-section, than around an arc as is found in a manifold of circular cross-section. Also, it is easier to assembly the heat exchanger tubes on a generally planar surface than on an arc. However, poor web strength remains a problem in manifolds of generally D-shaped cross-section, as it is in manifolds of generally circular cross-section.
The problem of poor web strength in manifolds of generally D-shaped cross-section is addressed in co-pending U.S. application Ser. No. 08/821,163, filed Mar. 20, 1997, now U.S. Pat. No. 5,881,456 entitled "Header Tubes for Heat Exchangers and the Methods Used for Their Manufacture" (Michael E. Bergins, inventor; attorney docket 18466.081), which is incorporated herein by reference in its entirety. In the manifolds disclosed in U.S. Pat. No. 5,881,456, the strength of the material is increased by stamping each side of each web with a stamping die. Furthermore, the webs are flattened such that the cross-section of the manifold segment has a D-shaped profile. However, U.S. Pat. No. 5,881,456 does not address the problem of inserting baffles into the resulting manifold, much less how to do so without incurring extra steps for securing the baffles once inserted, or without the need for machining separate slots in the tubular wall for insertion of the baffles.
Although U.S. application Ser. No. 08/842,041 addresses and solves these problems, the baffles disclosed therein will not reliably stay in place during the assembly process unless held in position by a mandrel. When a large number of baffles is to be inserted into a manifold, the repeated process of inserting the baffle and holding it in place with the mandrel, stamping the manifold to hold the baffle in place, and removing the mandrel can be inefficient.
The present invention provides an improvement over the invention disclosed in U.S. application Ser. No. 08/842,041 which eliminates the need for holding the baffle in place with a mandrel during assembly.